The present mounted stairway has a number of advantages over the prior art in that it is simple, adjustable, utilizes prefabricated parts which can be stored, shipped in bundle, and quickly mounted on site. The tested parts increase reliance and consequently reduce hazard in dwellings and industry as well.
The survey of the prior art shows that among few designs, the mounted stairway, as a structure, can be referred to the following inventions. U.S. Pat. No. 3,626,438 (Cornell) is an adjustable stairway which utilizes stairs with side supports in the form of adjustable parallelograms and therefore do not represent a rigid structure. In U.S. Pat. No. 4,631,880 (Leicht), the adjustable staircase includes a pair of channel section stringer members having spaced tread support pivots and tread locating apertures. Austrian Pat. No. 233229 (Lutz) utilizes railing brackets screwed in threaded sockets of concrete treads to accept railing posts, which may be considered unsafe. In U.S. Pat. No. 4,406,347 (Stathopoulos), the bracket is mounted directly to vertical support of the railing. A ladder stabilizer, disclosed in U.S. Pat. No. 3,456,757 (Sain), utilizes a boot which can be positioned by means of an arcuate slot cut in the angle wall.